I just sold a bicycle on Ebay and aside from a few obvious scammers I had a great experience as did the fellow who purchased the bike. I do think you are better off selling Hi Fi gear on Audiogon for rather obvious reasons.
There are many people out there that are, for lack of a better term, slobs. It does not occur to them that dust and dirt are a problem. They grew up in such an enviroment and they see it as normal. I think you can expect them to be more careless with their equipment and I would shy away from it particularly turntables, tonearms and cartridges. I do think the majority of us are meticulous with our gear.